1. Field of the Invention
The present invention relates to an endoscope apparatus that performs signal processing on image pickup means provided in an endoscope and generates an endoscope image.
2. Description of the Related Art
In recent years, electronic endoscopes equipped with image pickup means are widely used in various endoscope inspections or the like.
When performing an endoscope inspection using an electronic endoscope, various endoscope apparatuses are available such as a simultaneous type endoscope apparatus that picks up a color image using an image pickup device provided with a color optical filter under illumination of white light and a frame-sequential endoscope apparatus that picks up a color image under frame-sequential illuminating light of R, G and B using a monochrome image pickup device, and these endoscope apparatuses have different signal processing systems.
A conventional example in Japanese Patent Application Laid-Open Publication No. 2007-300972 discloses a simultaneous type endoscope apparatus. The conventional example in FIG. 1 adopts an endoscope having image pickup means provided with a complementary color filter and a signal processing apparatus for this image pickup means separates a luminance signal Y and a color signal C through a Y/C separation circuit.
Furthermore, this signal processing apparatus generates a luminance signal Yl obtained by passing the luminance signal Y through a low pass filter and a luminance signal Yh without the luminance signal Y passing through a low pass filter.
Furthermore, this signal processing apparatus adopts a configuration in which a selector 39 selects the luminance signal Yh or a luminance signal Ynbi in an observation mode of NBI outputted from a second matrix circuit 46 and outputs the selected signal to a next stage in conjunction with switching between observation modes of normal white light imaging (WLI) and narrow band imaging (NBI).